Answer:Hello My name is Marissa and im here to help!
Preservatives are natural or man-made chemicals that are added to foods to stop them from spoiling.
Explanation:hope this helps! brainliesst?
 
        
             
        
        
        
Discovery               In 1928 it was discovered by Frederick Griffith in an experiment generally known as transformation.
Experiment
                   In his experiment he considered two strains of <em>streptococus pneumonia,</em> one was R-type which was non-virulent and cause no disease in mice, other was virulent and S-type which cause disease and at last death of mice.
This experiment was comprised of four steps which are as follow:
 Step 1:           First he injected living strain of S into mice, after sometime mouce died.
Step 2:          He injected living strain of R into mice, the mice alive as he did not got any disease.
Step 3:         He injected heat killed strain of S into mice and mice remain alive.
Step 4:           He mixed living R strain with heat killed S strain and then inject into mice. As a result the mice died.
Conclusion:                  It was found that genetic material from heat killed S stain were transferred to living R (non-virulent) strain, as a result R become virulent and cause the death of mice.
 
        
             
        
        
        
Answer:
Explanation:
It is called a double circulatory system because blood passes through the heart twice per circuit. The right pump sends deoxygenated blood to the lungs where it becomes oxygenated and returns back to the heart. The left pump sends the newly oxygenated blood around the body.
 
        
             
        
        
        
Answer:
1. asexual, mitosis  2. sexual  3. gametes, meiosis  4. haploid 5. sex cells
Explanation:
Asexual reproduction is the form of reproduction that occurs whereby there is no fusion of gametes or a change in the number of chromosomes. The produced daughter cells are genetically similar to the parent. the form of cell division that occurs here is through a process of mitosis. 
Different organisms adopt different type of asexual reproduction including binary fission, spore formation, fragmentation etc. 
Sexual reproduction in contrast generates genetically unique organism through the fusion of two different organisms sex cells. To accomplish sexual reproduction, gametes that are haploid through a process of meiosis must be produced which are the egg cell and the sperm cells (the sex cells). These haploid cells are produced only in the germ cells to ensure the production of a diploid zygote.